You may be aware of this issue, but I've just discovered it this evening whilst enjoying downloading some wonderful apps. To date, I can only make this occur in the app store. Regardless, I plan on reporting this to the accessibility team next week. Briefly, if you've searched for something, but then want to find another app afterwards, and you clear the original text in the edit box, (obviously the clear text button has issues), VO will not respect your key echo settings, for example, I had it set to standard typing, letters and words, and it will announce the first tap of a letter and then when you double tap to enter the letter you only hear a soft clicking sound without the letter being echoed back to you. I've found this a time consuming bug if you are attempting to download multiple apps one after the other with the phone. I've also noticed this behavior using the system braille keyboard, where the phone will not announce anything but text is being entered because you can backspace through it. Curiously, I can only replicate this problem in the app store and not in Itunes or other system apps such as notes or messages. Not a horrible bug by any estimation, but a curious one nevertheless. Has anyone else seen this one appear? I know the original ios8 release had issues with not respecting key echo, so maybe this is a hangover from that not being addressed fully.
Apologies if my description is somewhat lacking, it is quite late here in the UK.